Adiabatic

ay-dee-uh-BAT-ik /ˌeɪdiəˈbætɪk/
adjectiveC2UPSC
FormalScientific

Relating to or denoting a process or condition in which heat is neither added nor removed from the system.

In an adiabatic process, any change in the system's internal energy is due solely to work done on or by the system, not to heat transfer. This can happen in a perfectly insulated system or a process that occurs very rapidly.

The story behind the word. The word 'adiabatic' comes from the Greek 'a-,' meaning 'not,' and 'diabainein,' meaning 'to pass through.' So, it literally means 'not passing through' or 'impassable.' It was coined by the physicist William John Macquorn Rankine in the mid-19th century to describe a process where heat cannot pass into or out of a system. It's a precise term for a perfectly insulated or very fast process.

Word relationships

  • Diathermic: Allowing heat to pass through readily, the opposite of adiabatic.
  • Isothermal: Occurring at constant temperature, which usually involves heat exchange.

Commonly confused with

  • Isothermal: Adiabatic means no heat exchange (Q=0), while isothermal means constant temperature (dT=0), which usually requires heat exchange.

Word family

  • adiabatically (adverb): in an adiabatic manner

Collocations

  • adiabatic process
  • adiabatic expansion
  • adiabatic compression
  • adiabatic wall
  • adiabatic lapse rate

Example sentences

  • "The rapid expansion of gas in a diesel engine's cylinder is an almost adiabatic process, as there is little time for heat exchange." Describing a thermodynamic process.
  • "As air rises in the atmosphere, it expands and cools adiabatically, leading to cloud formation." In atmospheric science.

Memory hook

ADIABATIC: A-DIA-BAT-ic. A BAT in a DIAmond-shaped, perfectly insulated box – no heat gets IN or OUT. No Heat Transfer

When not to use

Outside of highly technical scientific or engineering discussions. It's a specific term for a very particular thermodynamic condition.

Fun facts

  • The term 'adiabatic' is crucial in meteorology for understanding how air temperature changes with altitude.
  • A thermos flask is designed to be as close to an adiabatic system as possible, minimizing heat transfer.

Related words

Heat, System, Conservation

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